1. Field of the Invention
Embodiments of the invention relate to an organic light emitting diode display and a method of manufacturing the same.
2. Discussion of the Related Art
An organic light emitting element used in an organic light emitting diode (OLED) display has a self-emission structure in which a light emitting layer is formed between two electrodes. The organic light emitting element injects electrons from a cathode corresponding to an electron injection electrode and holes from an anode corresponding to an hole injection electrode into the light emitting layer and emits light when an exciton formed by a combination of the injected electrons and the injected holes falls from an excitation level to a ground level.
The OLED display using the organic light emitting element may be classified into a top emission type OLED display, a bottom emission type OLED display, and a dual emission type OLED display depending on an emitting direction of light. The OLED display may be classified into a passive matrix type OLED display and an active matrix type OLED display depending on a driving manner.
In the OLED display, when a scan signal, a data signal, a power, etc. are supplied to a plurality of subpixels arranged in a matrix form, selected subpixels of the plurality of subpixels emit light to thereby display an image.
Each of the subpixels includes a transistor unit including a switching transistor, a driving transistor, and a capacitor and an organic light emitting diode including a lower electrode connected to the driving transistor of the transistor unit, an organic light emitting layer, and an upper electrode. The organic light emitting layer generally includes a hole injection layer, a hole transfer layer, a light emitting layer, a electron transfer layer, and an electron injection layer, so as to facilitate an injection and a transfer of electrons and holes. In a related art organic light emitting layer, as it is easy to transfer energy in an interface between a light emitting layer and a hole transfer layer, a light emitting efficiency and lifetime of the OLED display are reduced because of an energy loss of triplet inside the OLED display.